public final class SingletonAtomizer extends UnaryExpression
operandEFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, INHERITED_CONTEXT, INSPECTION_CONTEXT, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, NAVIGATION_CONTEXT, NODE_VALUE_CONTEXT, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, W3C_CONSUMING, W3C_FREE_RANGING, W3C_GROUP_CONSUMING, W3C_MOTIONLESS, WATCH_METHOD| Constructor and Description |
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SingletonAtomizer(Expression sequence,
RoleLocator role,
boolean allowEmpty)
Constructor
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| Modifier and Type | Method and Description |
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PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.
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int |
computeCardinality()
Determine the static cardinality of the expression
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int |
computeSpecialProperties()
Determine the special properties of this expression
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Expression |
copy()
Copy an expression.
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AtomicValue |
evaluateItem(XPathContext context)
Evaluate as an Item.
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ExpressionCompiler |
getExpressionCompiler()
Return the compiler of the Cast expression
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String |
getExpressionName()
Give a string representation of the expression name for use in diagnostics
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ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by the expression, if possible
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RoleLocator |
getRole()
Get the RoleLocator (used to construct error messages)
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int |
getStreamability(int syntacticContext,
boolean allowExtensions,
List<String> reasons)
Get the "sweep" of this expression as defined in the W3C streamability specifications.
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StreamingAdjunct |
getStreamingAdjunct()
Get a class that supports streamed evaluation of this expression
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Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression
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Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Type-check the expression
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displayOperator, equals, explain, getBaseExpression, hashCode, iterateSubExpressions, promote, replaceSubExpression, toStringadoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getImplementationMethod, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, iterateSubExpressionInfo, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeErrorpublic SingletonAtomizer(Expression sequence, RoleLocator role, boolean allowEmpty)
sequence - the sequence to be atomizedrole - contains information about where the expression appears, for use in any error messageallowEmpty - true if the result sequence is allowed to be empty.public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify in class UnaryExpressionvisitor - an expression visitorXPathException - if an error is discovered during expression
rewritingpublic Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
typeCheck in class UnaryExpressionvisitor - an expression visitorcontextItemType - the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPEXPathException - if an error is discovered during this phase
(typically a type error)public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
UnaryExpressionThis method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.
optimize in class UnaryExpressionvisitor - an expression visitorcontextItemType - the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPEXPathException - if an error is discovered during this phase
(typically a type error)public int computeSpecialProperties()
computeSpecialProperties in class UnaryExpressionStaticProperty.NON_CREATIVE.public Expression copy()
copy in class Expressionpublic int getStreamability(int syntacticContext,
boolean allowExtensions,
List<String> reasons)
ExpressiongetStreamability in class ExpressionsyntacticContext - one of the values Expression.NAVIGATION_CONTEXT,
Expression.NODE_VALUE_CONTEXT, Expression.INHERITED_CONTEXT, Expression.INSPECTION_CONTEXTallowExtensions - if false, the definition of "guaranteed streamability" in the
W3C specification is used. If true, Saxon extensions are permitted, which make somereasons - the caller may supply a list, in which case the implementation may add to this
list a message explaining why the construct is not streamable, suitable for inclusion in an
error message.Expression.W3C_MOTIONLESS, Expression.W3C_CONSUMING,
Expression.W3C_GROUP_CONSUMING, Expression.W3C_FREE_RANGINGpublic StreamingAdjunct getStreamingAdjunct()
getStreamingAdjunct in class Expressionpublic RoleLocator getRole()
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
ExpressionThe default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
addToPathMap in class ExpressionpathMap - the PathMap to which the expression should be addedpathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be addedpublic AtomicValue evaluateItem(XPathContext context) throws XPathException
evaluateItem in class Expressioncontext - The context in which the expression is to be evaluatedXPathException - if any dynamic error occurs evaluating the
expressionpublic ItemType getItemType(TypeHierarchy th)
getItemType in class UnaryExpressionth - the type hierarchy cachepublic int computeCardinality()
computeCardinality in class UnaryExpressionStaticProperty.ALLOWS_ZERO_OR_ONE,
StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE,
StaticProperty.ALLOWS_ZERO_OR_MOREpublic String getExpressionName()
getExpressionName in class Expressionpublic ExpressionCompiler getExpressionCompiler()
getExpressionCompiler in class ExpressionCopyright (c) 2004-2013 Saxonica Limited. All rights reserved.